soldering a breech plug question

[zimmerstutzen]

hunter thompson: I realize that you are trying your best. It appears that you used a breech plug with 5/8 inch threads and then coated over the threads with metal somehow. This may seem like a good idea, but it simply isn't. A welded breech plug depends on the strength of the individual welds, each little bit of weld for each hundredth of an inch. That is a hundred places where the weld might not be that strong, or where a microscopic hole might permit corrosive powder fouling to seep into the joint and undermine it's strength. Even if you are a cracker jack welder, the breeching system is weak. Your threads should be at least 7/8, perhaps 1 inch. and you do not have enough barrel wall thickness for such threads. I once made a cannon barrel from an old piece of heavy walled steam drill pipe. As I recall a very high pressure piece of metal. I cut threads and put in a piece of a bolt as a breech plug. The cannon fired great for few years and then one day, I noticed the wad for over the powder went in the muzzle far easier than it had in the past. It swelled. The exterior showed tiny cracks and was about a 32 nd of an inch wider at the muzzle than at the breech. Another shot or two and it might have proved very bad. Have you checked to see how prone your schedule 40 would be to work hardening? What about the weld material? Can it work harden? As others have said, what you are planning is a very suspect and probably dangerous way to join a breech plug to the barrel. The barrel is not the optimum material. I would pass on this one and get the real barrel and breech plug and do t according to the text books about building and builders.

 

[hunter thompson]

So you have taken a cast hooked breech, welded a sleeve around the threads, and plan to weld that assembly into a piece of 3/4” schedule 40 stainless pipe (1.050” od x 0.113” wall x 0.824” id), correct? Interesting. Would really like to hear your plan for proofing the breech plug and barrel welded assembly.

thats right..proof is in the pudding

Every time you pull the trigger you will be weakening the weld, braze, or solder.
It's basically a time bomb.

yeah right keep dreaming i know its ok..i work with xray joints and 4000 lb air pressure in 4 inch pipe.

 

[hunter thompson]

hunter thompson: I realize that you are trying your best. It appears that you used a breech plug with 5/8 inch threads and then coated over the threads with metal somehow. This may seem like a good idea, but it simply isn't. A welded breech plug depends on the strength of the individual welds, each little bit of weld for each hundredth of an inch. That is a hundred places where the weld might not be that strong, or where a microscopic hole might permit corrosive powder fouling to seep into the joint and undermine it's strength. Even if you are a cracker jack welder, the breeching system is weak. Your threads should be at least 7/8, perhaps 1 inch. and you do not have enough barrel wall thickness for such threads. I once made a cannon barrel from an old piece of heavy walled steam drill pipe. As I recall a very high pressure piece of metal. I cut threads and put in a piece of a bolt as a breech plug. The cannon fired great for few years and then one day, I noticed the wad for over the powder went in the muzzle far easier than it had in the past. It swelled. The exterior showed tiny cracks and was about a 32 nd of an inch wider at the muzzle than at the breech. Another shot or two and it might have proved very bad. Have you checked to see how prone your schedule 40 would be to work hardening? What about the weld material? Can it work harden? As others have said, what you are planning is a very suspect and probably dangerous way to join a breech plug to the barrel. The barrel is not the optimum material. I would pass on this one and get the real barrel and breech plug and do t according to the text books about building and builders.

ive built 4000 lb air pressure pipes with x-ray joints.THE real barrel that you mention after i looked at them..i laugh...200.00 for them 1/4 the thickness.what a joke

 

[rich pierce]

Moderators please lock this thread. It has nothing to do with traditional muzzleloading.

 

[hunter thompson]

welded 100% ive had welders do xray joints filled with argon /inert gas..4000 lbs pressure..the welds dont fail..iam in the industry where 1000 of lives are at stake with failed joints.

 

[Alexander Efremenko]

I think the OP is going to do what he wants despite conventional and sound practices. We're arguing with a possum at this point.

 

[theoldredneck]

To the original question and logic behind it. Yes you can do the things you are asking about. I ask about some of these same things several years ago. I have bought some cheap imported muzzleloaders and a few built by individuals with welded breech plugs. Growing up older cousin owned welding machine shop. I was blessed to learn both how to weld and cut threads. The reason breech plugs and other things are threaded is strength. The length of the threaded plug and barrel area it screws into gives an increased surface area of contact between threads of barrel and plug. The pressure required to shear these threads is greater than the pressure required to burst the pipe. When a smooth plug is inserted into the same size pipe and welded 100 % at the weld joint it is strong I agree. Just not as strong because it does not have the depth of full bonding contact threads give. I'm not a engineer or rocket science major. My education is from both practical experience and classes. When I was warned against doing this it wasn't explained the way I tried to. So digging deeper I cut the barrel breech plugs that had been welded long ways. I was surprised that the slip fit areas were a mass of rust. Without threads firing had pushed the crud between the plug and barrel in that tiny crack. Cleaning allowed water in with it. On the outside looked great. Also where welds had been ground smooth they were very thin. Welds are only as strong as the thinnest point. In some applications threads are much stronger than welds. Breech plugs are one of these. I welded and threaded pipe for gas and liquids. This is a different situation with different type pressure loads/requirements. A gun firing is explosive instant pressure spikes. I pray this reference it understood. Years ago I watched a slow motion film of a 50 caliber BMG barrel being fired with a jacketed bullet and then with a solid copper bullet. The solid copper bullet going down the barrel looked like a snake swallowing a rat as it went down the barrel. The guy explained that though not as drastic all barrels expand and contract as the projectiles go through them. One of the earlier threads mentioned a barrel that had swelled and was cracking. I thought about what the guy said about all barrels expand and contract. About the rust and crud between slip fit welded plugs and barrels. There is strength in threads and wisdom in using them. I apologize for this being so long. I'm sure Zonie could have done better in less words.

 

[zimmerstutzen]

ive built 4000 lb air pressure pipes with x-ray joints.THE real barrel that you mention after i looked at them..i laugh...200.00 for them 1/4 the thickness.what a joke

quarter the thickness is absolutely not what you said above. You are going to do what you do regardless of advice here. If and when it blows up, if someone other than yourself is injured. You were warned and proceeded anyway. As I recall the criminal prosecutor need only prove wanton disregard of accepted safety standards..

 

[Kansas Kid]

I guess if you gonna do it use some Hastalloy W filler rod.

 

[JCKelly]

Hunter, do you have a wife/ Children? It's gonna be tough taking care of them, even if all you have is some brain damage from the breech as it passes through your eye..

Just out of curiosity, which particular grade of stainless are you using?

 

[Barry Strickland]

Hunter Thompson, I understand where you are coming from. BUT, ask yourself this, would the manufactures of muzzle loading guns go to all the trouble of cutting threads on the breech plug and cutting the internal threads in the barrel and then precision fit the breech face to the interior shoulder for no reason. It would cost one fifth as much to set up a submerged arc automatic welder to do the job.
I understand what you are saying, I worked many years at Cape Kennedy on swing arm hydraulics and high pressure systems and had many of the best X-Ray welders working for me. I retired as superintendent of mechanical construction and I understand what you are saying but you are dealing with explosive force here not static pressure. Please do not do this!

 

[F.G. Ford]

There are many things we do to make a rifle similar to an original of one hundred fifty years and much older. We do not necessarily use hammer forged iron barrels, we use modern made steel barrels much cheaper, and stronger.
We have learned not to weld barrels, as this causes stresses to the steel at the place of welding.
If we wish to attach some piece to the side of the barrel ( like a sight, or a lug ) we silver solder.
There are well founded reasons for these actions, and we don't stray for safety and common sense.
You guys can tell me NOT to put my finger in a loaded rat trap, or look down a canon barrel that has the fuse lit...............and I take your word for it.
To argue with you is without doubt foolish.
I have made quite a number of muzzle loaders, flint and percussion, and always safety is the main concern of the making of these guns.
We never know who is going to shoot these guns in the future. We know they are rated for black powder or a synthetic black powder ( MAYBE !!!!??? )
Every year we hear and see where some ***** loaded up a muzzle loader, even with a mild load of smokeless powder and an unfortunate situation came to be.
Even though someone on the internet said it was safe to do so.
Well sir, weld up the breech plug and give it to your son or daughter, and let them shoot it. I hope all goes well.
Because that is what is going to happen sooner or later. Someone's son or daughter is going to shoot that bomb, people like you will have a bewildered look on their face, and say it should not have happened.
Take pictures, so we all can learn. BUT don't say you didn't know.

 

[Powderburn]

I guess you can go ahead with your project, but for the love of GOD don’t let anyone else shoot it but YOU, and if you get tired of it, DESTROY it so some other innocent person can’t shoot it. It’s YOUR life and vision.....

And might I add to the above, DON'T have anyone else around when you shoot it!

 

[Zonie]

theoldredneck did a great job of explaining the problem with welding a bushing to a breech plug.
The weld will consist of only a small area of material where the sleeve or bushing is actually attached to the plug.
As the strength of the joint depends on the amount of volume of the joining weld, and that volume of material, consisting of only the weld material will be considerably less than a plug with the threads machined directly into it, the breech plug will be much weaker.

Every time the gun is fired, the material in that weld joint will be required to take the entire force developed by the exploding gunpowder. The load will be concentrated rather than spread out to many threads. This can lead to low cycle fatigue which can end up with the joint failing.

The same thing is true if the breech plug is welded to the barrel rather than threaded into it.

There are good reasons why the breech of a muzzleloader uses threads rather than a weld or brazed joint to retain it.

 

[Alexander Efremenko]

I think it is time to lock this thread up.
It is no longer productive

 

[SDSmlf]

Got to believe Hunter is just pulling our collective chains and isn’t serious about this. No one with any common sense or experience in metalworking would consider doing what he is suggesting. Plus he claims to have tremendous brazing/welding skills

have tremendous brazing/welding skills

but looking at his weld, don’t see it. Pretty rough. If I were claiming to be a skilled welder I would not post a photograph of that weld as an example of my work.

 

[John R]

Ummm my oh my.

I side with the naysayers.

My 55 years of working in a heavy industrial machine shop has me running scared.

I agree, lock this thread. It serves no purpose.

 

[hawkeye2]

To fit that breech plug to the back of the barrel requires grinding out almost all of the weld except that which has actually penetrated the plug and the sleeve. It is a little difficult to examine the original photo and blowing it up results in a fuzzy image. I have had a number of certs and tested a lot of welds when I worked at Pratt & Whitney and that doesn't look like a weld that would have a lot of penetration to me. Even if the weld held the silver solder joint would be in shear which is the absolute weakest configuration for a brazed joint (and yes, I've tested a lot of silver solder joints too).

 

[bpd303]

One thing not addressed is how is he going to deal with the HAZ of the pipe?

 

[sussexmuzllodr]

"Though from the presence of a foolish Man will not perceive in Him the Lips of Knowledge"